State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Geography, Beijing Normal University, Beijing, 100875, China.
Environ Monit Assess. 2014 Feb;186(2):971-8. doi: 10.1007/s10661-013-3431-9. Epub 2013 Sep 18.
Enrichment ratio (ER) is widely used in nonpoint source pollution models to estimate the nutrient loss associated with soil erosion. The objective of this study was to determine the ER of total nitrogen (ERN) in the sediments eroded from the typical soils with varying soil textures in Beijing mountain area. Each of the four soils was packed into a 40 by 30 by 15 cm soil pan and received 40-min simulated rainfalls at the intensity of 90 mm h(-1) on five slopes. ERN for most sediments were above unity, indicating the common occurrence of nitrogen enrichment accompanied with soil erosion in Beijing mountain area. Soil texture was not the only factor that influenced N enrichment in this experiment since the ERN for the two fine-textured soils were not always lower. Soil properties such as soil structure might exert a more important influence in some circumstances. The selective erosion of clay particles was the main reason for N enrichment, as implied by the significant positive correlation between the ER of total nitrogen and clay fraction in eroded sediments. Significant regression equations between ERN and sediment yield were obtained for two pairs of soils, which were artificially categorized by soil texture. The one for fine-textured soils had greater intercept and more negative slope. Thus, the initially higher ERN would be lower than that for the other two soils with coarser texture once the sediment yield exceeded 629 kg ha(-1).
浓缩比（ER）广泛应用于非点源污染模型中，用于估计与土壤侵蚀相关的养分流失。本研究旨在确定北京山区不同质地土壤侵蚀泥沙中总氮（ERN）的浓缩比。将 4 种土壤分别装入 40cm×30cm×15cm 的土盘，在 5 个坡度上接受强度为 90mm/h 的 40min 模拟降雨。大多数泥沙的 ERN 均大于 1，表明氮素在伴随土壤侵蚀发生富集是北京山区的普遍现象。土壤质地并不是影响本实验中氮素富集的唯一因素，因为两种细质地土壤的 ERN 并不总是较低。土壤性质（如土壤结构）在某些情况下可能会产生更重要的影响。粘土颗粒的选择性侵蚀是氮素富集的主要原因，这从侵蚀泥沙中总氮浓缩比与粘粒分数之间存在显著的正相关关系中可以看出。对于两对通过土壤质地人工分类的土壤，我们得到了 ERN 与泥沙产量之间的显著回归方程。对于细质地土壤，其截距更大，斜率更负。因此，一旦泥沙产量超过 629kg/ha，最初较高的 ERN 将低于其他两种质地较粗的土壤。
